KR20080109213A - Light emitting device and display device - Google Patents

Abstract

A light emitting device and a display device are provided to prevent damage of an anode electrode, and improve the brightness. A light emitting device(1000) comprises a first substrate(10), and a second substrate(12). The first substrate and the second substrate faced of each other. An electronics emission unit(100) is formed on the first substrate where electron-emissive elements forms an array. A light emitting unit(110) includes a side of a second substrate faced with the first substrate, an anode electrode(22), and a fluorescent layer(24). The light emitting unit comprises the fluorescent layer positioned in the single-side of the anode electrode, the partition(28), and a reflective film(30).

Description

LIGHT EMISSION DEVICE AND DISPLAY DEVICE}

1 is a partial cross-sectional view of a light emitting device according to an embodiment of the present invention.

2 is a partially exploded perspective view of a light emitting device according to another embodiment of the present invention.

3 is an exploded perspective view of a display device using the light emitting device shown in FIG. 2 as a light source.

The present invention relates to a light emitting device, and more particularly, to a light emitting device having an improved structure of an anode substrate and a display device using the same as a light source.

When all devices capable of recognizing that light is emitted from the outside are light emitting devices, light emitting devices are known in which a fluorescent layer and an anode electrode are formed on a front substrate, and electron emission parts and driving electrodes are formed on a rear substrate. . The light emitting device maintains the space between the front substrate and the rear substrate in a vacuum, and excites the fluorescent layer with electrons emitted from the electron emission unit to emit visible light.

The action of the light emitting device is to apply a driving voltage (scan driving voltage and data driving voltage) to the driving electrodes to control the electron emission amount of the electron emitting parts, and to apply a DC voltage (anode voltage) of several hundred to thousands of volts to the anode electrode. It is applied to accelerate the electrons emitted from the electron emission portion toward the fluorescent layer.

The light emitting device may be used as a light source for providing light to the display panel in a display device having a passive type display panel such as a liquid crystal display panel.

Such a light emitting device has low power consumption, is advantageous for large size, and has a simple structure of an optical member, compared to a case of using a cold cathode fluorescent lamp (CCFL) and a light emitting diode (LED). have.

In the light emitting device, the anode electrode mainly consists of a metal film such as aluminum. The anode electrode is deposited while covering the fluorescent layer or the fluorescent layer and the black layer to reflect the visible light emitted toward the first substrate among the visible light emitted from the fluorescent layer to increase the brightness of the screen. After the formation of the fluorescent layer, the anode electrode is completed by forming an interlayer on the layers, depositing a metal on the interlayer, and then removing the interlayer by firing. That is, the anode electrode is not in contact with the fluorescent layer by the intermediate film, and has a substantially flat surface.

However, the interlayer has a problem of damaging the anode electrode due to its thickness and swelling upon firing or reducing the luminance of the phosphor layer by contacting the anode electrode and the phosphor particles.

The present invention provides a light emitting device capable of suppressing damage to an anode electrode and increasing a brightness of a screen while reducing the inconvenience of a process, and a display device having the same.

The light emitting device according to the embodiment of the present invention includes a first substrate and a second substrate disposed opposite to each other, an electron emission unit provided on the first substrate, and a light emitting unit provided on the second substrate. The light emitting unit includes a reflective film formed on the second substrate and a partition formed between the second substrate and the reflective film.

The light emitting unit may include a fluorescent layer and a black layer, and the partition wall may be formed on the black layer.

In addition, the light emitting device may include a plurality of light emitting regions for emitting light, and a non-light emitting region positioned between the plurality of light emitting regions and formed in a lattice shape, and the partition wall may be formed to correspond to the non-light emitting region.

The reflective film may be provided as a sheet and attached to the partition wall.

The height of the barrier rib may be greater than the thickness of the fluorescent layer, and the barrier rib may be 100 μm to 1000 μm.

The reflective film may be a metal sheet.

On the other hand, the display device according to an embodiment of the present invention includes a display panel for displaying an image, and a light emitting device for providing light to the display panel. Here, the light emitting device may be formed in the above-described configuration.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art can easily understand, the embodiments described below may be modified in various forms without departing from the concept and scope of the present invention. Where possible, the same or similar parts are represented using the same reference numerals in the drawings.

When a portion is said to be "on" another portion, it may be just above the other portion or may be accompanied by another portion. In contrast, when a part is mentioned as "directly above" another part, no other part is intervened in between.

It is to be understood that the terms first, second and third are used to describe various parts, components, regions, layers and / or sections, but are not limited to these. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, the first portion, component, region, layer or section described below may be referred to as the second portion, component, region, layer or section without departing from the scope of the invention.

The terminology used herein is for reference only to specific embodiments and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the term "comprising" embodies a particular characteristic, region, integer, step, operation, element, and / or component, and other specific characteristics, region, integer, step, operation, element, component, and / or group. It does not exclude the presence or addition of.

Terms indicating relative space such as "below" and "above" may be used to more easily explain the relationship to other parts of one part shown in the drawings. These terms are intended to include other meanings or operations of the device in use with the meanings intended in the figures. For example, when the device in the figure is reversed, any parts described as being "below" of other parts are described as being "above" other parts. Thus, the exemplary term "below" encompasses both up and down directions. The device can be rotated 90 degrees or at other angles, the terms representing relative space being interpreted accordingly.

Unless defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly defined terms used are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted as ideal or very formal meaning unless defined.

In the embodiment of the present invention, the light emitting device includes all devices capable of recognizing that light is emitted when viewed from the outside. Therefore, the devices of all displays that display information by displaying symbols, letters, numbers, and images, are also included in the light emitting device. In addition, the light emitting device may be used as a light emitting panel that provides light to the light receiving display panel. The light emitting panel includes a flat panel or a curved panel. Other types of panels may be included.

1 is a partial cross-sectional view of a light emitting device 1000 according to an embodiment of the present invention.

Referring to FIG. 1, the light emitting device 1000 according to the present exemplary embodiment includes a first substrate 10 and a second substrate 12 disposed to face each other in parallel with each other at a predetermined interval. The 1st board | substrate 10 and the 2nd board | substrate 12 are joined by the sealing member 14 arrange | positioned at the edge, and comprise the container which has an internal space. The vessel is evacuated to a vacuum of approximately 10 ⁻⁶ Torr to constitute a vacuum vessel 1100 composed of a first substrate 10, a second substrate 12, and a sealing member 14.

The surface of the first substrate 10 facing the second substrate 12 is provided with an electron emission unit 100 in which an array of electron emission elements is arranged, and the second substrate 12 facing the first substrate 10. The light emitting unit 110 includes an anode electrode 22, a fluorescent layer 24, and the like on the surface of the substrate.

The first substrate 10 provided with the electron emission unit 100 and the second substrate 12 provided with the light emitting unit 110 are combined to form the light emitting device 1000.

The electron emission unit 100 includes an electron emission unit 20 and driving electrodes 16 and 22. The driving electrodes 16 and 22 control the amount of electron emission of the electron emission unit 20. The driving electrode includes a gate electrode 22 formed along the direction intersecting the cathode electrode 16 on the cathode electrode 16 with the cathode electrode 16 and the insulating layer 18 therebetween.

As a result, an intersection region of the cathode electrode 16 and the gate electrode 22 is formed, and this intersection region may constitute one pixel region of the light emitting device 1000. Openings 221 and 181 are formed in the gate electrode 22 and the insulating layer 18 in each crossing region to expose a portion of the surface of the cathode electrode 16. The electron emission part 20 is positioned on the cathode electrode 16 inside the insulating layer opening 181.

The electron emission unit 20 is formed of materials that emit electrons when an electric field is applied in a vacuum, such as a carbon-based material or a nanometer (nm) size material. That is, the electron emission unit 22 is made of a material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond phase carbons, fullerenes (C ₆₀ ), silicon nanowires, and combinations thereof.

On the other hand, the electron emission portion may be formed of a tip structure having a pointed tip mainly made of molybdenum (Mo) or silicon (Si).

Next, the light emitting unit 110 includes an anode electrode 22, a fluorescent layer 24 located on one surface of the anode electrode 22, a partition wall 28, and a reflective film 30.

The anode electrode 22 receives a high voltage required for electron beam acceleration from the outside, for example, a voltage of 10 kV to 20 kV to maintain the fluorescent layer in a high potential state. The anode electrode 22 is formed of a transparent conductive film such as indium tin oxide (ITO).

On the contrary, the fluorescent layer and the anode electrode may be alternately stacked. When the fluorescent layer and the anode electrode are sequentially stacked on the second substrate, the fluorescent layer is adjacent to the second substrate. Accordingly, since the anode does not interfere with light emitted from the fluorescent layer, the anode may be formed of an opaque metal having good electrical conductivity.

The fluorescent layer 24 is formed over the anode electrode. The fluorescent layer 24 is formed by, for example, fluorescent layers of red 24R, green 24G, and blue 24B at arbitrary intervals from each other. A black layer 26 is formed between the fluorescent layers 24R, 24G, and 24B to improve contrast of the screen. The fluorescent layer 24 may correspond to one unit pixel for each unit pixel set in the first substrate 10.

In the present embodiment, a partition wall 28 having a predetermined height is formed on the fluorescent layer 24, and a reflective film 30 is formed on the partition wall 28.

Specifically, the partition wall 28 has a height of 100 μm to 1000 μm to correspond to the portion of the black layer 26 formed on the second substrate 12. The height of the partition wall 28 protrudes from the second substrate 12 from the second substrate 12 along the −z axis direction so as to be greater than the thickness of the fluorescent layer 24. As a result, each of the fluorescent layers 24R, 24G, and 24B is separated from each other by the partition walls 28 from adjacent fluorescent layers 24R, 24G, and 24B.

The reflective film 30 is attached to the bottom surface (xy surface) of the partition wall 28. Here, an aluminum (Al) sheet or the like may be used as the reflective film 30, and the reflective film 30 may be attached to the partition wall 28 using an adhesive or the like. In addition, fine holes are formed in the reflective film 30 to pass the electron beam. The reflective film 30 reflects the visible light emitted toward the first substrate 10 of the visible light emitted from the fluorescent layer 24 toward the second substrate 12 to increase the luminance of the light emitting surface.

By the above-described structure, the reflective film 30 may be formed without contacting the fluorescent layer 24 by the partition wall 28, and each of the fluorescent layers 24R, 24G, and 24B may be the partition wall 28 and the reflective film ( 30, each of the independent cells can be formed. Therefore, it is possible to prevent a phenomenon in which visible light emitted from each of the fluorescent layers 24R, 24G, and 24B spreads to adjacent fluorescent layers 24R, 24G, and 24B.

In addition, a space S is formed between the fluorescent layer 24 and the reflective film 30 by the partition wall 28. This space (S) facilitates the flow of air so that high temperature thermal process such as firing can be actively carried out. Accordingly, in the process of firing the second substrate 12 including the light emitting unit 110, an adhesive (not shown) may be cured to firmly adhere the reflective film 30 to the partition wall 28. Moreover, gases that decompose in the adhesive upon firing can be discharged smoothly.

In this embodiment, the sheet-type reflective film 30 is attached onto the fluorescent layer 24. As a result, contamination of the fluorescent layer 30 can be prevented as compared with the case where a metal such as aluminum is deposited on the fluorescent layer 24 to form the reflective film 30. In addition, since the partition wall 28 is disposed on the fluorescent layer 30, it is not necessary to form an intermediate film for the space S between the fluorescent layer 24 and the reflective film 30.

Meanwhile, in the present embodiment, the height of the partition wall 28 is illustrated and described as being larger than the thickness of the fluorescent layer 24, but is not limited thereto. For example, in a structure in which the partition is formed on the black layer, when the height of the sum of the black layer and the partition wall is larger than the thickness of the fluorescent layer, the height of the partition wall may be smaller than the thickness of the fluorescent layer.

The above-described light emitting device 1000 applies a predetermined driving voltage to the cathode electrode 16 and the gate electrode 22, and drives the anode electrode 22 by applying a direct current voltage of a quantity of thousands of volts or more.

For example, the scan driving voltage is applied to one of the cathode electrodes 16 and the gate electrodes 22, and the other electrodes apply the data driving voltage.

Then, an electric field is formed around the electron emission unit 20 in the unit pixels in which the voltage difference between the cathode electrode 16 and the gate electrode 22 is greater than or equal to the threshold value. As a result, as shown in FIG. Electrons e- are emitted. The emitted electrons (e−) are attracted to the high voltage applied to the anode electrode 30 to impinge on the corresponding fluorescent layer 24 to emit the fluorescent layer 24.

In the above driving process, each of the fluorescent layers forms an independent space by the partition wall, so that the reflection efficiency is improved and the fluorescent layer corresponding to the electron emission part can be accurately emitted.

As described above, the light emitting device 1000 including the red fluorescent layer 24R, the green fluorescent layer 24G, and the blue fluorescent layer 24B to display an image by itself is described as an embodiment. It can also be used as a light source for providing white light to the display panel.

2 shows a partially disassembled light emitting device 1000 ′ for the light source.

Referring to FIG. 2, in the light emitting device 1000 ′ of the light source, the electron emission unit 100 may include an electron emission unit electrically connected to the cathode electrode 16, the gate electrode 22, and the cathode electrode 16. 20). The light emitting unit 110 includes an anode electrode 22, a fluorescent layer 24 ′ emitting white light, a partition wall 28, and a reflective film 30.

The fluorescent layer 24 ′ may be formed of a mixed phosphor that emits white light by mixing a red phosphor, a green phosphor, and a blue phosphor. It may be located in the entire effective region of the second substrate 12.

In the light emitting device 1000 ′, the first substrate 10 and the second substrate 12 may be positioned at relatively large intervals of 5 to 20 m. The arc discharge in the vacuum chamber may be reduced by increasing the distance between the first substrate 10 and the second substrate 12, and a high voltage of 10 kV to 20 kV may be applied to the anode electrode 22. The light emitting device 1000 ′ may realize a maximum luminance of approximately 10,000 cd / m 2 at the center of the effective area.

FIG. 3 is a schematic exploded view of a display device 2000 according to an exemplary embodiment including the light emitting device 1000 ′ shown in FIG. 2.

Referring to FIG. 3, the display device 2000 includes a light emitting device and a display panel.

Referring to FIG. 3, the display device 2000 includes a light emitting device 1000 ′ and a display panel 200. The display device 2000 further includes a first fixing member 302 and a second fixing member 304 to fix and support the display panel 200 and the light emitting device 1000 ′. A diffuser plate 400 is provided between the display panel 200 and the light emitting device 1000 ′ to diffuse light emitted from the light emitting device 1000 ′ to be supplied to the display panel 200. The diffusion plate 400 and the light emitting device 1000 ′ are spaced apart from each other by a predetermined distance.

The display panel 200 includes a liquid crystal display panel or another light receiving display panel. Hereinafter, the case where a display panel is a liquid crystal display panel as an example is demonstrated.

The display panel 200 includes a TFT substrate 210 including a plurality of thin film transistors (TFTs), a color filter substrate 220 positioned on the TFT substrate 210, and an injection therebetween. And a liquid crystal layer (not shown). Polarizers (not shown) are attached to the upper portion of the color filter substrate 220 and the lower portion of the TFT substrate 210 to polarize light passing through the display panel 200.

The TFT substrate 210 is a transparent glass substrate on which a thin film transistor on a matrix is formed, a data line is connected to a source terminal, and a gate line is connected to a gate terminal. In the drain terminal, a pixel electrode made of a transparent conductive film as a conductive material is formed.

When electrical signals are input from the printed circuit boards 230 and 240 to the gate line and the data line, respectively, electrical signals are input to the gate terminal and the source terminal of the TFT. According to the input of these electrical signals, the TFT is turned on or turned off, and the electrical signals necessary for pixel formation are output to the drain terminal.

The color filter substrate 220 is a panel in which RGB pixels, which are color pixels in which a predetermined color is expressed while light passes, are formed by a thin film process, and a common electrode made of a transparent conductive film is coated on the entire surface thereof.

When power is applied to the gate terminal and the source terminal of the TFT and the thin film transistor is turned on, an electric field is formed between the pixel electrode and the common electrode of the color filter substrate 220. The array angle of the liquid crystal injected between the TFT substrate 210 and the color filter substrate 220 is changed by the electric field, and the light transmittance is changed for each pixel according to the changed array angle.

The printed circuit boards 230 and 240 of the display panel 200 are connected to gate lines and data lines through respective driving IC packages 2301 and 2401. In order to drive the display panel 200, the gate printed circuit board 230 transmits a gate driving signal, and the data printed circuit board 240 transmits a data driving signal.

The light emitting device 1000 ′ is a light source for supplying light to the display panel 200. The light emitting device 1000 ′ can be driven for each light emitting pixel as indicated by a dotted line. A plurality of gate lines (not shown) and a plurality of data lines (not shown) are formed in the light emitting device 1000 ′, and they are connected to a printed circuit board (not shown) through the driving integrated circuit packages 102 and 104. . The printed circuit board is positioned on the rear surface of the light emitting device 1000 ′. The printed circuit board operates the light emitting device 1000 'by applying driving signals to the gate line and the data line of the light emitting device 1000'.

The light emitting device 1000 ′ forms fewer pixels than the display panel 200 such that one pixel of the light emitting device 1000 ′ corresponds to two or more pixels of the display panel 200. Each pixel of the light emitting device 1000 ′ may emit light corresponding to the highest gray level among the pixels of the display panel 200 corresponding thereto, and the light emitting device 1000 ′ may display gray levels of 2 to 8 bits for each pixel. I can express it.

For convenience, a pixel of the display panel 200 is referred to as a first pixel, a pixel of the light emitting device 1000 ′ is referred to as a second pixel, and a plurality of first pixels corresponding to one second pixel is called a first pixel group. do.

A driving process of the light emitting device 1000 will be described below. In the light emitting device 1000 ′, a signal controller (not shown) controlling the display panel 200 detects the highest gray level among the first pixels of the first pixel group. The grayscale required for the emission of the second pixel is calculated according to the detected grayscale, and is converted into digital data. And generating driving signals of the light emitting panel using the digital data.

The driving signal of the light emitting device 1000 ′ includes a scan driving signal and a data driving signal. By the driving signals, the second pixel of the light emitting apparatus 1000 ′ emits light with a predetermined gray level in synchronization with the first pixel group when an image is displayed in the corresponding first pixel group. As described above, the light emitting apparatus 1000 ′ independently controls the light emission intensity of each pixel to provide light of an appropriate intensity to the pixels of the display panel 200 corresponding to each pixel. Therefore, the display device of the present embodiment can increase the contrast of the screen and can realize a clearer picture quality.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

The light emitting device according to the embodiment of the present invention can form a space between the fluorescent layer and the reflective film without forming the intermediate film. In addition, by providing an optimal height of the partition wall, each of the fluorescent layers may be formed as an independent cell to accurately emit the fluorescent layer corresponding to the electron emission unit. In addition, since a space is formed between the fluorescent layer and the reflective film by the partition wall, it is possible to smoothly flow the air during firing, thereby reducing the material that is outgassed into the sealed light emitting device.

In addition, the display device using the above-described light emitting device as a light source can increase the dynamic aspect ratio of the screen to improve the display quality, reduce the power consumption of the light emitting device to lower the overall power consumption and can be easily manufactured as a large display device. Can be.

Claims (12)

A first substrate and a second substrate disposed to face each other; An electron emission unit provided on the first substrate; And Light emitting unit provided on the second substrate Including, The light emitting unit A reflective film formed on the second substrate; And Barrier rib formed between the second substrate and the reflective film Light emitting device comprising a. The method of claim 1, The light emitting unit includes a fluorescent layer and a black layer, and the partition wall is formed on the black layer. The method of claim 1, The light emitting device includes a plurality of light emitting regions for emitting light; And A non-light emitting area disposed between the plurality of light emitting areas and formed in a lattice shape Including, The barrier rib is formed to correspond to the non-light emitting area. The method of claim 1, The light emitting device provided with the reflective film is attached to the partition wall. The method of claim 1, The light emitting device of which the height of the partition is larger than the thickness of the fluorescent layer. The method of claim 5, The partition of the light emitting device having a height of 100㎛ to 1000㎛. The method of claim 1, The light emitting device wherein the reflecting film is a metal sheet. A display panel displaying an image; And A light emitting device that provides light to the display panel Including, The light emitting device, A first substrate and a second substrate disposed to face each other; An electron emission unit provided on the first substrate; And Light emitting unit provided on the second substrate Including, The light emitting unit A reflective film formed on the second substrate; And Barrier rib formed between the second substrate and the reflective film Display device comprising a. The method of claim 8, The light emitting device includes a plurality of light emitting regions for emitting light; And A non-light emitting area disposed between the plurality of light emitting areas and formed in a lattice shape Including, The barrier rib is formed to correspond to the non-light emitting area. The method of claim 8, The display device includes the reflective film attached to the partition wall. The method of claim 8, And a height of the partition wall is greater than a thickness of a fluorescent layer formed in the light emitting unit. The method of claim 11, A display device of which the height of the barrier rib is 100 µm to 1000 µm.

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